Preparation Of Composites Consisted Of Special Structure Ti_O2 And Nano-carbon Material And Application Research In Purifying Contamianted Water

Environmental and energy issues are two major problems that people needed to solve, how to deal the unnatural contaminated wastewater with low concerntration and high toxicity have still plagued people. Owing to non-toxic, environmentally and rapidly, semiconductor photocatalyst have become an important means of dealing with contaminated wastewater. Although titanium dioxide（TiO₂） is acclaimed with non-toxic, well photocatalytic effect and stable. However, the large band gap and limit its practical applications. With such advantages as high stability, high strength, high specific surface and wide sources, nano-carbon material become potential for development. Graphene and carbon nanotubes were concerned because of its unique one and two dimensional nature. We systhesis of TiO₂ having a special structure through hydrothermal and successfully composite with graphene and carbon nanotube used for removel of oil and POPs in water environment. The details are summarized as follows:（1） Using NaBH₄ as reducing agent, we successfully prepared super-long and curced TiO₂ nanowires/r GO composite under continuous stirring through one step hydrothermal method. After being dried, using nitrogen as protective gas, TiO₂ nanowires/rGO with high crystalline, large specific surface was achieved by being caclined in resistive tube furnace at a low temperature. The optimum fabrication conditions were expored by adjusting the molar ratio of reducing agent. Photocatalytic performance of the resulting TiO₂/r GO composites was evoluatedin oil contaminated water. The content of the oil be adsorbed by measuring the COD of the sample. It`s found that the catalyst with best catalytic efficiency was prepared when the reducing agent added in amount of was 100 mM. The COD of the water decreased with increasing adding amount of the catalyst. When the catalyst was 3 g/100 ml, the oil removal efficiency reached 85.9%. The result determined by IR spectrometer show that the TiO₂/RGO exhibits a self-purification capacity under the sunlight.（2） TiO₂ microspheres with large specific surface area were using diethyl lenetriamine as surfactant, tetrabutyl as titanium source, preparing hierarchical through simple hydrothermal and successfully composite with different qualities of carbon nanotubes（CNTs） form TiO₂/CNTs. Using the excellent electron transport capacity of CNTs we build electron transport network between TiO₂ hierarchical microspheres. The binary complex catalyst was used to remove 4NP（POPs） in water environment, when CNTs was added in amount of 5%, 4NP degradation efficiency reached 97%. In this article we also discussed effects of pH and different concentrations of 4NP, obtained when pH=3, 5 mg/L¹0 mg/L（4NP） has the best degradation, and found that in the process of degradation ·OH play a major role, ·O₂- and h+ play a secondary role.（3） We also degration nitrophenol, aminophenol and 2-chloro-4amino-phenol these three kinds of phenolic compounds with different substituents in sunlight to disscuss the degration effect of different substituents on the phenyl ring. We found that the degradation efficiency was related to the nature of substituents with donor/acceptor electrons on the phenyl ring. The donor electrons will make electron cloud density increases and easier be attacked by electron-poor group such as·OH and h+, which is easier to edgrate the target pollutants.